When Rex Fortescue dies while sitting at his desk in the City, it's determined that he was in fact poisoned. He was married to a much younger wife, who now stands to inherit. His son Percival, a partner in the family firm, was a disappointment to him and a daughter, Elaine, hasn't amounted to much. Another son, Lance, had a falling out with his father many years before and relocated to East Africa. He suddenly appears soon after his father's death claiming that they had reconciled and been invited by him to return to England with an offer to rejoin the firm. Miss Marple takes a particular interest in the case when her former maid Gladys, now working in the Fortescue household, is also murdered. She soon learns that the elder Fortescue had received veiled threats for some time and that they might have something to do with a long ago business deal that made his initial fortune.